The present invention relates generally to timing circuits and more particularly, to means for compensating for the chattering of mechanical switches used in conjunction with timing circuits.
Electronic timing circuits are in widespread use in many different areas of technology and when used in mechanisms having moving parts, such as cameras, care must be taken to prevent disruption of the current flow due to switch chatter caused by the mechanical motion of the moving parts within the associated mechanism. For example, in electronic cameras utilizing electronic switching and timing circuits, these circuits are normally energized and deenergized through the synchronized action of mechanical switches which are actuated in dependence upon the position of a shutter release lever, the position of the shutter-opening mechanism, the position of the shutter-closing mechanism as well as the position of other movable parts within the camera. Due to the various types of movement and the high speed with which the parts are moved, vibrations and other spurious movements are imparted to the various camera components thereby causing undesired switch chatter. Switch chatter, or contact chatter as it is sometimes referred to, is the undesirable opening and closing of the switch contacts which usually results in current disruption or current oscillation in the associated circuitry.
In order to compensate for switch chatter, it is now a known practice to connect capacitors in parallel with the mechanical switches so that during switch chatter, charging current can flow to the capacitors thereby maintaining an uninterrupted current flow in the associated circuitry. This technique has proven effective in nullifying the effect of switch chatter however has the drawback that numerous capacitors are needed thereby increasing the number of parts and hence increasing the manufacturing cost of the circuits.